How to fix Character Length in a TextBox

Posted 18 Jun '10 - 22:11

Solution 8

1.To restrict maxlength of textbox with three character, write

<asp:TextBox ID="TextBox1" runat="server" MaxLength="3"></asp:TextBox>

2.To match exactly three character in textbox add following javascript function

function checkLength(obj) {
            if (obj.value.length != 3) {
                alert("Should be exactly three char.");
                obj.focus();
            }
        }

And call the function in onblur event

TextBox1.Attributes.Add("onblur", "checkLength(this)");

3.To allow only text in textbox add following javascript function

function handleKeydown(event) {
            keyEntry = event.keyCode || event.which;
            if (
                ((keyEntry >= '65') && (keyEntry <= '90')) ||
                ((keyEntry >= '97') && (keyEntry <= '122')) ||
                (keyEntry == '46') ||
                (keyEntry == '32') ||
                keyEntry == '45' ||
                keyEntry == '46' ||
                keyEntry == '8' ||
                keyEntry == '35' ||
                keyEntry == '36'||
                keyEntry == '9')
                return true;
            else
                return false;
        }

And add onkeydown & onpaste handler in code behind

TextBox1.Attributes.Add("onkeydown", "return handleKeydown(event)");
TextBox1.Attributes.Add("onpaste", "return handleKeydown(event)");

Hope this will help you.

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Posted 30 Jun '10 - 1:34

Prosanta Kundu online5.8K

Solution 1

touseef4pk wrote:
Say i want to restrict to 3 three characters. It should not only to enter less than or more than three characters.

There are many ways:
1) Use Javascript - Write code onblur of the textbox to check if the length is equal to 3 or not.

<asp:TextBox ID="TextBox1" runat="server" onblur="javascript:validate();"></asp:TextBox>

function validate()
    {
        if(document.getElementById("TextBox1").value.length != 3)
        {
            alert("text lenghth must be three");
            document.getElementById("TextBox1").select();
            document.getElementById("TextBox1").focus();
            return false;
        }
        else
        {
            return true;
        }
    }

2) Use RegularExpressionValidator. You need to write a regular expression which checks the value entered is 3 characters.

[Edit]

touseef4pk wrote:
Please tell me how can i write reqular expression to limit characters upto three characters in textbox

Try this: \b[a-zA-Z]{3}\b

[/Edit]

touseef4pk wrote:
I want to allow only text in the textbox.

Text means alphanumeric which is the default for a textbox.
I guess you don't mean that. Please clarify.

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Posted 18 Jun '10 - 23:56

Ankur^\m/44.2K

Edited 20 Jun '10 - 20:21

Solution 2

Thanks for reply. Please tell me how can i write reqular expression to limit characters upto three characters in textbox. Actualy I mean to say that the input shoule be alphabetical only like "The". It should not accept numeric values. Please help me to resolve this conflict.

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Posted 19 Jun '10 - 1:03

touseef4pk1.3K

Comments

Ankur\m/ - 21 Jun '10 - 2:13

You should use comment to discuss with a user. I didn't get a notification for your answer and chances was very low that I would have seen your question again. You see you will get a notification for the comment. Similarly I would have been notified if you commented my answer. Try this regular expression: [a-zA-Z]{3} (Add a backslash b at the start and end. I don't know why this is not displayed in the comment or wait I am adding it to my previous answer). And yes if an answer, answers your question completely, you should choose "Accept Answer" and you may also vote high for it. Cheers!

Solution 3

For an example on a implenting a validator, see here.

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Posted 19 Jun '10 - 6:43

Abhinav S331K

Solution 5

You can add javascript regex validation.

Try "^[a-zA-Z]{3}$" as regular expression for your text box.
This regex will allow only 3 alphabet character.

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Posted 21 Jun '10 - 22:34

Ronak Bhavsar469

Solution 6

Dear.
Please set maxLength properties of Textbox. if you set this 3 then it will not allow to enter more than three characters.

For allowing only text, use AjaxControlToolkit. you can download from microsoft download.

In ajaxcontrolToolkit, you have to use FilterTextBox. You have to defined the type as 'Integer','Text'.....

check this link

http://www.asp.net/(S(fu2l2uzphr2u3u45q2dnez55))/ajax/AjaxControlToolkit/Samples/[^]

and click on FilteredTextBox

Hope it will help you.

Thanks

Lalit Kumar

Permalink

Posted 21 Jun '10 - 23:34

Lalit Kumar 5733889

Comments

Ankur\m/ - 30 Jun '10 - 6:52

Reason for my vote of 2 The OP needs EXACTLY 3 characters.

Solution 7

For 3 Character length use

 Maxlength="3"

property in textbox
and for character only i think

AJAX:FilterTextboxExtender

control will work

Permalink

Posted 30 Jun '10 - 0:40

Arun S Rana414

Comments

Ankur\m/ - 30 Jun '10 - 6:51

Reason for my vote of 1 The OP needs EXACTLY 3 characters. Moreover you have put same answer as above poster(Lalit)

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How to fix Character Length in a TextBox

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How to fix Character Length in a TextBox

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